Hey VaultDoors :)

Interesting Bunker, you have there :D Okay, about the material:

1. If you want to have it made of aluminum, the size cant be the original, because of the weight. BUT on the other hand you have the nice metal feeling when you touch it.
2. If you take wood (beech would be good), the scale could be much bigger, so more at the size of the original RCV.

To your questions:

1. Yes
2. At least the knobs should rotate
3. Depends on the detail of the interior.
4. Yes
5. Not necessarily.

Best regards

Maik